The present specification relates to terrain warning systems. Conventionally, pilots use terrain warning systems such as terrain awareness and warning systems (TAWS), ground proximity warning systems (GPWS), and enhanced GPWS (EGPWS). Terrain warning systems have been designed to provide critical information to pilots and flight crews to reduce aviation accidents related to controlled flight into terrain.
Terrain warning systems generally can provide visual and audio warnings to prevent controlled flight into terrain. Terrain warning systems generally are coupled with a visual display and an audio system and receive positional information related to the aircraft's actual or relative position. Terrain warning systems receive various input criteria about location (e.g., latitude, longitude, and altitude) of the aircraft as well as its speed and direction of travel (e.g., heading). Terrain warning systems map the input criteria to a terrain database. The result can be used to indicate that the aircraft is in danger of hitting the terrain as represented by the terrain database.
The visual or audio warning issued by the terrain warning system can include instructions for evasive maneuvers to the pilot. The warnings can be generated from a conventional terrain awareness algorithm or from a radio altitude/aircraft state system.
The terrain warning system can receive input criteria from a variety of sources. For example, the aircraft's position can be provided by a flight management system, a global positioning system, an inertial navigation system, pilot input, or any other position sensing device. In addition, redundant sensors can be utilized. For example, altitude can be determined both from a GPS system and an onboard altimeter.
The terrain database can be referenced to particular locations (e.g., latitude, longitude, altitude, etc.) and stored on non-volatile memory such as hard drives. Some databases are local or regional while others are global. Generally, conventional terrain warning systems have utilized databases based upon information generated prior to the flight of the aircraft. Some of the data can be relatively old and require updated information related to man-made objects, such as buildings, radio towers, bridges, etc. Such systems can be prone to false alarms due to database inaccuracy/resolution and missed hazardous states due to new terrain obstacle/features.
Accordingly, there is a need for a system that can generate an in-flight estimate of terrain elevation for a TAWS, RTAWS, or GPWS. There is also a need to determine a terrain elevation estimate using an aircraft sensor. There is further a need to sense terrain elevation in real time or pseudo real time for a terrain warning system. Yet further, there is a need for an accurate low cost method of generating terrain elevation.
It would be desirable to provide a system and/or method that provides one or more of these or other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the aforementioned needs.